1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2%YAML 1.2 3--- 4$id: http://devicetree.org/schemas/media/video-interface-devices.yaml# 5$schema: http://devicetree.org/meta-schemas/core.yaml# 6 7title: Common bindings for video receiver and transmitter devices 8 9maintainers: 10 - Jacopo Mondi <jacopo@jmondi.org> 11 - Sakari Ailus <sakari.ailus@linux.intel.com> 12 13properties: 14 flash-leds: 15 $ref: /schemas/types.yaml#/definitions/phandle-array 16 description: 17 An array of phandles, each referring to a flash LED, a sub-node of the LED 18 driver device node. 19 20 lens-focus: 21 $ref: /schemas/types.yaml#/definitions/phandle 22 description: 23 A phandle to the node of the focus lens controller. 24 25 rotation: 26 $ref: /schemas/types.yaml#/definitions/uint32 27 enum: [ 0, 90, 180, 270 ] 28 description: | 29 The camera rotation is expressed as the angular difference in degrees 30 between two reference systems, one relative to the camera module, and one 31 defined on the external world scene to be captured when projected on the 32 image sensor pixel array. 33 34 A camera sensor has a 2-dimensional reference system 'Rc' defined by its 35 pixel array read-out order. The origin is set to the first pixel being 36 read out, the X-axis points along the column read-out direction towards 37 the last columns, and the Y-axis along the row read-out direction towards 38 the last row. 39 40 A typical example for a sensor with a 2592x1944 pixel array matrix 41 observed from the front is: 42 43 2591 X-axis 0 44 <------------------------+ 0 45 .......... ... ..........! 46 .......... ... ..........! Y-axis 47 ... ! 48 .......... ... ..........! 49 .......... ... ..........! 1943 50 V 51 52 The external world scene reference system 'Rs' is a 2-dimensional 53 reference system on the focal plane of the camera module. The origin is 54 placed on the top-left corner of the visible scene, the X-axis points 55 towards the right, and the Y-axis points towards the bottom of the scene. 56 The top, bottom, left and right directions are intentionally not defined 57 and depend on the environment in which the camera is used. 58 59 A typical example of a (very common) picture of a shark swimming from left 60 to right, as seen from the camera, is: 61 62 0 X-axis 63 0 +-------------------------------------> 64 ! 65 ! 66 ! 67 ! |\____)\___ 68 ! ) _____ __`< 69 ! |/ )/ 70 ! 71 ! 72 ! 73 V 74 Y-axis 75 76 with the reference system 'Rs' placed on the camera focal plane: 77 78 ¸.·˙! 79 ¸.·˙ ! 80 _ ¸.·˙ ! 81 +-/ \-+¸.·˙ ! 82 | (o) | ! Camera focal plane 83 +-----+˙·.¸ ! 84 ˙·.¸ ! 85 ˙·.¸ ! 86 ˙·.¸! 87 88 When projected on the sensor's pixel array, the image and the associated 89 reference system 'Rs' are typically (but not always) inverted, due to the 90 camera module's lens optical inversion effect. 91 92 Assuming the above represented scene of the swimming shark, the lens 93 inversion projects the scene and its reference system onto the sensor 94 pixel array, seen from the front of the camera sensor, as follows: 95 96 Y-axis 97 ^ 98 ! 99 ! 100 ! 101 ! |\_____)\__ 102 ! ) ____ ___.< 103 ! |/ )/ 104 ! 105 ! 106 ! 107 0 +-------------------------------------> 108 0 X-axis 109 110 Note the shark being upside-down. 111 112 The resulting projected reference system is named 'Rp'. 113 114 The camera rotation property is then defined as the angular difference in 115 the counter-clockwise direction between the camera reference system 'Rc' 116 and the projected scene reference system 'Rp'. It is expressed in degrees 117 as a number in the range [0, 360[. 118 119 Examples 120 121 0 degrees camera rotation: 122 123 124 Y-Rp 125 ^ 126 Y-Rc ! 127 ^ ! 128 ! ! 129 ! ! 130 ! ! 131 ! ! 132 ! ! 133 ! ! 134 ! ! 135 ! 0 +-------------------------------------> 136 ! 0 X-Rp 137 0 +-------------------------------------> 138 0 X-Rc 139 140 141 X-Rc 0 142 <------------------------------------+ 0 143 X-Rp 0 ! 144 <------------------------------------+ 0 ! 145 ! ! 146 ! ! 147 ! ! 148 ! ! 149 ! ! 150 ! ! 151 ! ! 152 ! V 153 ! Y-Rc 154 V 155 Y-Rp 156 157 90 degrees camera rotation: 158 159 0 Y-Rc 160 0 +--------------------> 161 ! Y-Rp 162 ! ^ 163 ! ! 164 ! ! 165 ! ! 166 ! ! 167 ! ! 168 ! ! 169 ! ! 170 ! ! 171 ! ! 172 ! 0 +-------------------------------------> 173 ! 0 X-Rp 174 ! 175 ! 176 ! 177 ! 178 V 179 X-Rc 180 181 180 degrees camera rotation: 182 183 0 184 <------------------------------------+ 0 185 X-Rc ! 186 Y-Rp ! 187 ^ ! 188 ! ! 189 ! ! 190 ! ! 191 ! ! 192 ! ! 193 ! ! 194 ! V 195 ! Y-Rc 196 0 +-------------------------------------> 197 0 X-Rp 198 199 270 degrees camera rotation: 200 201 0 Y-Rc 202 0 +--------------------> 203 ! 0 204 ! <-----------------------------------+ 0 205 ! X-Rp ! 206 ! ! 207 ! ! 208 ! ! 209 ! ! 210 ! ! 211 ! ! 212 ! ! 213 ! ! 214 ! V 215 ! Y-Rp 216 ! 217 ! 218 ! 219 ! 220 V 221 X-Rc 222 223 224 Example one - Webcam 225 226 A camera module installed on the user facing part of a laptop screen 227 casing used for video calls. The captured images are meant to be displayed 228 in landscape mode (width > height) on the laptop screen. 229 230 The camera is typically mounted upside-down to compensate the lens optical 231 inversion effect: 232 233 Y-Rp 234 Y-Rc ^ 235 ^ ! 236 ! ! 237 ! ! |\_____)\__ 238 ! ! ) ____ ___.< 239 ! ! |/ )/ 240 ! ! 241 ! ! 242 ! ! 243 ! 0 +-------------------------------------> 244 ! 0 X-Rp 245 0 +-------------------------------------> 246 0 X-Rc 247 248 The two reference systems are aligned, the resulting camera rotation is 249 0 degrees, no rotation correction needs to be applied to the resulting 250 image once captured to memory buffers to correctly display it to users: 251 252 +--------------------------------------+ 253 ! ! 254 ! ! 255 ! ! 256 ! |\____)\___ ! 257 ! ) _____ __`< ! 258 ! |/ )/ ! 259 ! ! 260 ! ! 261 ! ! 262 +--------------------------------------+ 263 264 If the camera sensor is not mounted upside-down to compensate for the lens 265 optical inversion, the two reference systems will not be aligned, with 266 'Rp' being rotated 180 degrees relatively to 'Rc': 267 268 269 X-Rc 0 270 <------------------------------------+ 0 271 ! 272 Y-Rp ! 273 ^ ! 274 ! ! 275 ! |\_____)\__ ! 276 ! ) ____ ___.< ! 277 ! |/ )/ ! 278 ! ! 279 ! ! 280 ! V 281 ! Y-Rc 282 0 +-------------------------------------> 283 0 X-Rp 284 285 The image once captured to memory will then be rotated by 180 degrees: 286 287 +--------------------------------------+ 288 ! ! 289 ! ! 290 ! ! 291 ! __/(_____/| ! 292 ! >.___ ____ ( ! 293 ! \( \| ! 294 ! ! 295 ! ! 296 ! ! 297 +--------------------------------------+ 298 299 A software rotation correction of 180 degrees should be applied to 300 correctly display the image: 301 302 +--------------------------------------+ 303 ! ! 304 ! ! 305 ! ! 306 ! |\____)\___ ! 307 ! ) _____ __`< ! 308 ! |/ )/ ! 309 ! ! 310 ! ! 311 ! ! 312 +--------------------------------------+ 313 314 Example two - Phone camera 315 316 A camera installed on the back side of a mobile device facing away from 317 the user. The captured images are meant to be displayed in portrait mode 318 (height > width) to match the device screen orientation and the device 319 usage orientation used when taking the picture. 320 321 The camera sensor is typically mounted with its pixel array longer side 322 aligned to the device longer side, upside-down mounted to compensate for 323 the lens optical inversion effect: 324 325 0 Y-Rc 326 0 +--------------------> 327 ! Y-Rp 328 ! ^ 329 ! ! 330 ! ! 331 ! ! 332 ! ! |\_____)\__ 333 ! ! ) ____ ___.< 334 ! ! |/ )/ 335 ! ! 336 ! ! 337 ! ! 338 ! 0 +-------------------------------------> 339 ! 0 X-Rp 340 ! 341 ! 342 ! 343 ! 344 V 345 X-Rc 346 347 The two reference systems are not aligned and the 'Rp' reference system is 348 rotated by 90 degrees in the counter-clockwise direction relatively to the 349 'Rc' reference system. 350 351 The image once captured to memory will be rotated: 352 353 +-------------------------------------+ 354 | _ _ | 355 | \ / | 356 | | | | 357 | | | | 358 | | > | 359 | < | | 360 | | | | 361 | . | 362 | V | 363 +-------------------------------------+ 364 365 A correction of 90 degrees in counter-clockwise direction has to be 366 applied to correctly display the image in portrait mode on the device 367 screen: 368 369 +--------------------+ 370 | | 371 | | 372 | | 373 | | 374 | | 375 | | 376 | |\____)\___ | 377 | ) _____ __`< | 378 | |/ )/ | 379 | | 380 | | 381 | | 382 | | 383 | | 384 +--------------------+ 385 386 orientation: 387 description: 388 The orientation of a device (typically an image sensor or a flash LED) 389 describing its mounting position relative to the usage orientation of the 390 system where the device is installed on. 391 $ref: /schemas/types.yaml#/definitions/uint32 392 enum: 393 # Front. The device is mounted on the front facing side of the system. For 394 # mobile devices such as smartphones, tablets and laptops the front side 395 # is the user facing side. 396 - 0 397 # Back. The device is mounted on the back side of the system, which is 398 # defined as the opposite side of the front facing one. 399 - 1 400 # External. The device is not attached directly to the system but is 401 # attached in a way that allows it to move freely. 402 - 2 403 404additionalProperties: true 405 406... 407